Selenium compound antifoggant for silver halide emulsion

ABSTRACT

R1, R2, AND R3 EACH REPRESENTING ALKYL, ARALKYL OR ARYL AND X-IS AN ANION WHEN R ITSELF DOES NOT CONTAIN AN ANIONIC GROUP. THESE PHOTOGRAPHIC MATERIALS HAVE DECREASED FORGGING TENDENCY, EVEN UNDER CONDITIONS OF HIGH TEMPERATURE AND HUMIDITY, AND THEIR SENSITIVITY IS PRACTICALLY NOT LOWERED BY THE PRESENCE OF THESE SELENIUM COMPOUNDS.   -P(+)(-R1)(-R2)(-R3) X(-)   PHOTOGRAPHIC MATERIAL ARE PROVIDED WHICH COMPRISE IN A LIGHT-SENSITIVE SILVER HALIDE EMULSION LAYER OR IN AN ADJACENT WATER-PERMEABLE LAYER A SELENIUM COMPOUND OF THE FORMULA R-SE-Q WHEREIN R STAND FOR ALKYL, ARALKYL, ALKARYL OR ARYL WHICH MAY BE SUBSTITUTED BY HALOGEN, SULPHO, CARBOXYL OR NITRO OR FORM PART OF A HETEROCYCLIC RING SYSTEM AND O STANDS FOR HALOGEN, CYANA OR

United States Patent Int. Cl. G03c 1/34 US. Cl- 96-109 14 Claims ABSTRACT OF THE DISCLOSURE Photographic materials are provided which comprise in a light-sensitive silver halide emulsion layer or in an adjacent water-permeable layer a selenium compound of the formula RSeQ wherein R stands for alkyl, aralkyl, alkaryl or aryl which may be substituted by halogen, sulpho, carboxyl or nitro or form part of a heterocyclic ring system and Q stands for halogen, cyana or R R and R each representing alkyl, aral'kyl or aryl and X- is an anion when R itself does not contain an anionic group. These photographic materials have decreased fogging tendency, even under conditions of high temperature and humidity, and their sensitivity is practically not lowered by the presence of these selenium compounds.

This invention relates to improved photographic materials comprising light-sensitive silver halide emulsions, more particularly to photographic materials having less tendency to fog formation.

It is well known that light-sensitive silver halide materials comprising gelatin silver halide emulsion layers are subjected fogging. Fogging in general and chemical fogging in particular may be defined as the formation of a uniform deposit of silver on development which is dependent on a whole series of circumstances and factors namely on the nature of the emulsions, on their age, on the conditions under which they have been stored, on the development conditions, etc. For particular development conditions the fog tends to be greater as the time of storage and the temperature and relative humidity of the atmosphere, in which the emulsions are stored, are increased.

Addenda to the photographic material known as stabilizers or antifoggants protect the light-sensitive silver halide emulsions against formation and growth of fog particularly in high-sensitive emulsions and in emulsions which are to be stored under conditions of high temperature and humidity as is for instance the case in tropical countries.

In accordance with the invention it has been found that selenium compounds corresponding to the following general formula:

RSeQ wherein:

R stands for alkyl, aralkyl, alkaryl, or aryl which may carry further substituents selected from halogens, e.g. chlorine and bromine, sulpho, carboxyl and nitro, or form part of a heterocyclic ring system, and

3,681,078 Patented Aug. 1, 1972 ice Q stands for an electron-withdrawing atom or group with strong leaving properties selected from halogen such as bromine, CEN, and

/R1 -1 R, X-

Ra wherein each of R R and R stands for alkyl, aralkyl or aryl and X- stands for an anion but does not exist when R itself contains an anionic group, are particularly good antifoggants for photographic lightsensitive silver halide emulsions without giving rise to an appreciable desensitization thereof.

The compounds having the structures below are representative of those falling within the scope of the above general formula. They can be prepared as described in the literature referred to.

Cl-Q-Se-ON BrQSe-CN Arkiv. Kemi, 25, 363 (1966).

Ber. 65, 812 (1932).

Ber. 60, 708 (1933).

J. Chem. 800.,1648 (1926);

J. Chem. 800., 1648(1926).

This compound can be prepared as follows:

0.05 mole of tributylphosphine selenide and 0.1 mole of propane sultone were heated for 30 min. at 100 C. The oil obtained was treated with ether and then with acetone. The precipitate formed was dried over phosphorus trioxide. The tributylphosphine selenide used was prepared by allowing to react equimolecular amounts of tributylphosphine and selenium in toluene, first at room tem perature and then by reflux. The solution was filtered and the toluene removed by evaporation. The remaining liquid was distilled under reduced pressure. The tributylphosphine selenide has a boiling point of 177 C./0.75 mm. 9. oHs

nao-se-i -otn, -C-H3SO4' CaHn This compound can be prepared as follows:

0.03 mole of triphenylphosphine selenide prepared as described in Inorg. Synth., 10, 157 (1967) in 15 g. of dimethyl sulphate was heated for 30 min. at C. The solution obtained was treated, after having been cooled,

with ether whereupon the white precipitate formed was washed with ether and dried.

N(CHz)z-SeCN l d Ber., 2 4, 213a (1801) NC-Se- This compound can be prepared as follows:

22 g. of 2-methyl-6-aminobenzthiazole in 80 m1. of 5 N hydrochloric acid and 400 ml. of water were diazotised at 0 C. with a solution of g. of sodium nitrite in 20 ml. of water whereupon the solution was buffered to pH 4 by means of 75 g. of sodium acetate. A solution of 28.8 g. of potassium selenocyanate in 50 ml. of water was added and the precipitate formed was filtered by suction. The product was recrystallized from ethylene glycol monomethyl ether.

Melting point: 137 C.

The compounds according to the present invention are generally incorporated into the silver halide emulsion layer of the light-sensitive material. The way in which the compounds of use according to the invention are added to emulsions is not critical and the addition can be made during no matter what step of emulsion preparation; they can be added before or after the emulsion has been optically sensitized, preferably just before coating of the emulsion on a suitable support such as for example paper, glass or film.

Instead of incorporating the compounds of the invention into the emulsion layer they can also be incorporated into another layer of the photographic material, e.g. a gelatin anti-stress layer or intermediate layer, which is in water-permeable relationship with the said emulsion layer or into one of the processing baths for said photographic material.

The antifoggants of use according to the present invention may be incorporated into any type of light-sensitive material comprising a silver halide emulsion layer e.g. a spectrally sensitized or non-sensitized silver halide emulsion layer, a silver halide emulsion layer of use in diifusion transfer processes for the production of silver images, an X-ray emulsion layer, and an emulsion layer sensitive to infrared radiation. They may be incorporated into high speed negative materials as well as into rather low speed positive materials. Various silver salts may be used as light-sensitive salt e.g. silver bromide, silver iodide, silver chloride, or mixed silver halides e.g. silver chlorobromide or silver bromoiodide.

The silver halides are dispersed in the common hydrophilic colloids such as gelatin, casein, zein, polyvinyl alcohol, carboxymethylcellulose, alginic acid, etc., gelatin being, however, favoured.

The amount of antifoggant employed in the light-sensitive silver halide material depends on the particular type of emulsion and the desired effect and can vary within very wide limits. The optimum amount of antifoggant to be added is best determined for each particular type of emulsion by trial. Generally, the most suitable concentration is between 0.05 millimole and 20 millimoles preferably between 0.1 and 10 millimoles of antifoggant per kg. of silver halide emulsion.

The light-sensitive emulsions may be chemically as well as optically sensitized. They may be chemically sensitized by effecting the ripening in the presence of small amounts of sulphur containing compounds such as allyl thiocyanate, allyl thiourea, sodium thiosulphate, etc. The emulsions may also be sensitized by means of reductors for instance tin compounds as described in our United Kingdom Patent specification 789,823 and small amounts of noble metal compounds such as of gold, platinum, palladium, iridium, ruthenium and rhodium.

Other addenda such as hardening agents, wetting agents, plasticizers, colour couplers, developing agents and optical sensitizers can be incorporated into the emulsion in the usual way.

The antifoggants according to the present invention are particularly suitable for use in conjunction with compounds which sensitize the emulsion by development acceleration for example alkylene oxide polymers. These alkylene oxide polymers may be of various type. Various derivatives of alkylene oxides may be used to sensitize the silver halide emulsions e.g. alkylene oxide condensation products as described among others in United States patent specifications 2,5 3 1,832 and 2,533,990, in United Kingdom patent specifications 920,637, 940,051, 945,340 and 991,608 and in Belgian patent specification 648,710. Other compounds that sensitize the emulsion by development acceleration and that are suitable for use in combination with the antifoggants of use according to the invention are the onium derivatives of amino-N-oxides as described in United Kingdom patent specification 1,121,696.

The stabilizers according to the invention can also be used in conjunction with other known stabilizers for instance with heterocyclic nitrogen containing thioxo compounds such as benzothiazoline-Z-thione and l-phenyl-A tetrazoline-S-thione, with mercury compounds such as those described in Belgian patent specifications 524,121 and 677,337 and in Belgian patent specifications 707,386 and 709,195 and preferably with compounds of the hydroxytriazolopyrimidine type (hydroxyazaindolizines), particularly in extreme storage and development circumstances such as 5 methyl-7-hydroxy-s-triazolo[1,5-a]- pyrimidine.

In the following examples the values of the fog produced in photographic materials incorporating compounds corresponding to the above general formula is illustrated as compared with the values of the fog producing in photographic materials comprising 5-methyl-7-hydroxys-triazolo[1,5-a]pyrimidine which is known to have favourable antifoggant properties.

EXAMPLE 1 A conventional photographic gelatino silver bromoiodide emulsion (4.5 mole percent iodide) comprising per kg. an amount of silver halide equivalent to 50 g. of silver nitrate was divided into three portions A, B and C. To emulsion portion A no antifoggant was added whereas to emulsion portions B and C the antifoggant listed in the table below was added. Then the emulsions were coated on a conventional support and dried.

The values of the fog produced in the materials A, B and C formed were determined shortly after preparation and after incubation for 5 days at 57 C. and 34% relative humidity. The values obtained are listed in the table below.

Development occurred at 20 C. for 5 min. in a develop ing solution having the following composition:

EXAMPLE 2 Example 1 was repeated with the difference that the emulsion was divided into four aliquot portions to which the compounds listed in the table below were added in the Example 1 was repeated with the dilference that the emulsion was divided into three aliquot portions to which the compounds listed in the table below were added in silver nitrate to gelatin of 1 to 3 and applied to a barytacoated paper support in such a way that after drying an amountof silver halide equivalent to 1.9 g. of silver nitrate was present per sq. m.

The results obtained are listed in the table.

TABLE Fresh material Stored material Compound added per Gra- Grakg. emulsion Fog dation Speed Fog dation Speed None 0. 21 4.01 134 0.39 3. 32 130 1 mmole of Compound 6 0. 11 3. 19 140 0. 11 3. 67 137 1 mmole of Compound 4.. 0. 2. 88 141 0. 09 3.25 134 3mmoles of Compound 4.- 0. 07 2. 83 142 0. 07 2. 60 135 1 mmole of Compound 3.. 0. 07 2. 92 142 0. 11 3. 22 136 EXAMPLE 6 Example 5 was repeated with the difference that development now lasted 4 min.

The following results were obtained.

the concentration given.

Fresh material Stored material TABLE Compound added per Gra- Gra Fog produced in kg. emulsion 0g dation Speed Fog dation Speed Mmole/ Fresh Incubated None 0. 11 3. 81 137 0. 22 4. 17 142 Material Antifoggant kg. material material lnunole of Compound 2 0.06 3. 56 142 0.12 3. 28 143 1 mmole of Compound 3-. 0.05 2. 83 144 0. 06 3. 78 144 A. 0. 27 1. 56 1 mmole of Compound 4.- 0. 05 2. 78 143 0. 07 2. 67 144 B Compound3 0.1 0.16 0.23 3mmolesof Compound4 0.05 2.37 145 0.05 2.64 143 C 5-methy1-7-hydroxy-s- 1 0. 22 0. 57 1 mmole of Compound 5 0.05 2. 97 140 0. 06 3.48 145 triazolo[1,5-a]py'rim1dlne. 3 mmoles of Compound 0 0. l..- i "1.1-. 0.05 3. 17 148 0. 07 2. 98 135 mmo e0 om oun The following examples illustrate the favourable and 11 0.05 2. 57 14a 0. 00 3.44 142 fogging action of the compounds of use according to the present invention and show that the sensitivity of the We claim:

emulsions to which said compounds were added is not reduced to a noteworthy extent. The values given for the speed are exposure value corresponding with density 0.7 above fog; a decrease of the value by 30 means a doubling of the speed.

EXAMPLE 4 A gelatino silver bromoiodide emulsion (3 mole percent of iodide) prepared with a proportion of silver nitrate to gelatin of 1 to 3 (31.6 g./94.8 g. per kg. of emulsion) was divided into several portions. To each portion a compound as listed in the table below was added in the concentration given whereupon the emulsion portions were applied to a baryta-coated paper support in such a way that after drying an amount of silver halide corresponding to 2.2 g. of silver nitrate was present per sq. m.

The values of speed, gradation and fog of the materials formed were determined shortly after preparation and after storing for 3 days at 67 C. and 60 percent relative humidity. The values obtained are listed in the table below.

Development occurred at 20 C. for 8 min. in a developing solution having the following composition:

Water C.) ml 800 p-Monomethylaminophenol sulphate g-.. 1.5 Sodium sulphite (anhydrous) g 25 Hydroquinone a 6 Sodium carbonate (anhydrous) g 40 Potassium bromide g 1 Water to make 1000 ml.

TABLE Fresh material Stored material Compound added per Gra- Grakg. emulsion Fog dation Speed Fog dation Speed None 0. 10 3. 56 91 0. 20 3.55 85 1 mmole of Compound 2 0. 07 3. 14 101 0. 11 3. 16 90 1 mmole of Compound 4.- 0. 06 3. 31 104 0. 09 3. 65 00 3 moles of Compound 1.. 0. 10 2. 76 90 0. 12 2. 38 88 6 mmoles of Compound 1.- 0. 08 2. 92 90 0. 13 2. 40 91 EXAMPLE 5 Example 4 was repeated with the difference that now a gelatino silver chloroiodide emulsion (0.4 mole percent of iodide) was used prepared with a proportion of 1. Photographic material comprising a support having at least one light-sensitive silver halide emulsion layer thereon comprising in said emulsion layer or in a. waterpermeable layer coated at the same side of the support as the said emulsion layer in an amount suflicient to inhibit fogging a compound corresponding to the following general formula:

RSeQ i wherein:

8 stands for alkyl, aralkyl, alkaryl, or aryl, which may be substituted by halogen, sulpho, carboxyl or nitro, or form part of a heterocyclic ring, and

Q stands for halogen, cyano, or

R: wherein each of R R and R stands for alkyl, aralkyl or aryl and X'- stands for an anion but does not exist when R itself contains an anionic group.

2. Photographic material according to claim 1, wherein said material also comprises a hydroxytriazolo py rimidine stabilizer.

3. Photographic material according to claim 1 Wherein said material also comprises a polyoxyalkylene development accelerator.

4. Photographic material according to claim 1, wherein said emulsion layer is a gelatino silver halide emulsion layer.

5. In the method of producing photographic images which comprises imagewise exposing to radiation a photograiphic radiation-sensitive silver halide material having a support coated with water-permeable colloid layers including a radiation-sensitive silver halide emulsion layer, and processing the same so as to produce a visible image therein, the improvement wherein said processing takes place in the presence of a compound in an amount sufficient to inhibit fogging according to the general formula:

wherein:

R stands for alkyl, aralkyl, alkaryl, or aryl, which may be substituted by halogen, sulpho, carhoxyl or nitro, or form part of a heterocyclic ring, and Q stands for halogen cyano, or

wherein each of R R and R stands for alkyl, aralkyl or aryl and X- stands for an anion but does not exist when R itself contains an anionic group.

6. In the method according to claim 5, the further improvement wherein said processing takes place in the presence of a hydroxytriazolopyrimidine stabilizer.

-7. In the method according to claim 5, the further improvement wherein said processing takes place in the presence of a polyoxyalkylene development accelerator.

8. Photographic material according to claim 1 wherein R stands for alkyl.

9. Photographic material according to claim 1 wherein R stands for aryl.

-10. Photographic caterial according to claim 1 wherein Q is cyano.

11. Photographic material according to claim 8 Wherein Q is cyano.

12. Photographic material according to claim 9 wherein Q is cyano.

13. In the method according to claim 5, the further improvement wherein R is alkyl and Q is cyano.

14. In the method according to claim 5, the further improvement wherein R is aryl and Q is cyano.

References Cited UNITED STATES PATENTS 2,195,150 6/1939 Kendall 96109 1,713,613 5/1929 Meyer 9666.5 X 2,057,764 10/1936 Brunken 96109 3,284,206 11/1966 Blake 96107 U.S. Cl. XiR. 9650, 66.3 

